Heat exchanger assembly



Oct. 9, 1956 ADAMS ET AL 2,766,019

HEAT EXCHANGER ASSEMBLY Filed March 23, 1955 2 Sheets-Sheet 1 Fee. l

INVENTORS: RICHARD F ADAMS MASON M. RANDLE 1956 R. F. ADAMS ET A2,766,019

HEAT EXCHANGER ASSEMBLY Filed March 23, 1955 2 Sheets-Sheet 2 IN V ENTORS' RICHARD F. ADAMS MASON M. RANDLE ban.

FEAT EXCGER ASSEMBLY Richard F. Adams and Mason M. Randle, Alton, 111.,as-

signors to Olin Mathieson Chemical Corporation, East Alton, Ill, acorporation of Virginia Application March 23, 1955, Serial No. 496,213

6 Claims. ((11. 257-256) This invention relates to structuralfabrication and more specifically to means for connecting hollow unitssuch as heat exchangers.

It has previously been the practice in connecting the units of a heatexchanger system to provide an entirely separate return system withexternal piping from the last unit of the system back to the supplysource. In systems which attempted to incorporate a portion of thereturn system integrally with evaporator plates of the type disclosed inU. S. Patent 2,690,002 it was necessary to provide an externalperipheral opening into the plates for both the supply and returnsystems. This has the obvious disadvantages in the fabrication andassembly of the system of requiring additional external joint openingsin the units and the connection of the additional joints, as well astending to permit excessive ice formation in refrigeration units at thesupply system joints.

It is therefore an object of this invention to reduce the number ofexternal connections required in each heat exchanger unit, therebyreducing the possibility of external leaks. Another object of thisinvention is to reduce the number of positive connections, such aswelded, threaded or bolted joints required to join the connectingconduits such as pipes or tubes to the units. Another object of thisinvention is to eliminate, so far as possible, exposed piping and tomake practicable the use of flexible or pliable tubing which is easierto work with and more resistant to breakage. Another object of thisinvention is to achieve a substantial reduction in the undesirable,uneven heat conditions at the joints between the units. Another objectof this invention is to provide a heat exchanger system made up ofindividual units, which is inexpensive to fabricate and assemble. Otherobjects and advantages will become apparent from the description andaccompanying drawings in which:

Figure l is a plan view partially in section of one embodiment of theinvention.

Figure 2 is a sectional plan view of a modified form of an individualjoint.

Figure 3 is a cross-sectional view taken on the line III-III in Figure1.

Figure 4 is a sectional plan view of another modified form of anindividual joint.

Figure 5 is a sectional plan view of still another modified form of anindividual joint.

The foregoing objects are accomplished by a novel assembly of connectingtubing and a plurality of heat exchanger units. These units preferablyare of the type disclosed in U. S. Patents Nos. 2,662,273 or 2,690,002,although any type unit may be adapted for use in conjunction with thisinvention. The first unit of the system has a fluid passageway orconduit the two ends of which each, in one modification, open into oneof two special tube connection cavities each of which is of greaterdiameter than the diameter of the conduit at the point of juncture withthe cavity. The first unit i atented Oct. 9, 1956 is joined to a secondunit by an inner conduit such as a pipe or tube which passes through oneconnection cavity in each unit and frictionally engages one of thepassageway openings in the respective connection cavity to provide asubstantially fluidtight joint. In a similar manner any intermediateunits are connected between the first and last units of the series.Obviously the heat exchanger units may also be connected in parallel toa supply source. The only variation between the first, intermediate andlast units is that in the last unit the passageway which opens into aconnector cavity, as previously described, has its other end openinginto a side of the same cavity rather than into a second cavity as inthe first or intermediate units. A larger outer conduit encases and isspaced from each inner conduit and has each end received in the adjacentcavity of each unit through which an end of the smaller conduit passes.The larger conduit is welded to the mouth of the cavity, or otherwisepositively attached thereto. The larger conduit may merely frictionallyengage the inner surface of the cavity, if desired. As a main supply anddischarge connection, a conduit is received in the remaining connectioncavity in the first unit and is frictionally seated in a passageway inthis cavity to form a substantially fiuidtight joint while anotherlarger conduit encases and is spaced from the inner conduit and isreceived in the adjacent connection cavity in the first unit. If desiredan additional heat exchanger unit may be attached in place of the abovedescribed supply and discharge piping, with the supply and dischargeconnections being made to the initial unit of the series. The first unitand each intermediate unit is provided with a second integrally formedconduit opening into the two cavities to complete a fluid circuitthrough all the units of the series.

The invention will be better understood from the following detaildescription:

In Figures 1 and 3, heat exchanger units such as unit 1, which may befabricated from any suitable material, but preferably aluminum orcopper, are provided with a fluid carrying passageway, or conduit 2,having a configuration resembling a heat exchanger coil. One end of theconduit 2 opens into and joins a peripheral connection cavity 3 whilethe other end opens into and joins a peripheral connection cavity 4.Connection cavities 3 and 4 open out through a peripheral edge 5 ofunit 1. Connecting the cavities 3 and 4 is a second passageway or pipe 6which opens into both the cavities 3 and 4 at a point spaced from theperipheral opening and intermediate the sheet periphery 5 and the heatexchange passageway or pipe 2.

A return unit 7 is provided with a conduit 9, one end of which opensinto the cavity 3 in the same manner as conduit 2 opens into eithercavity 3 or 4. The basic difference between the return unit 7 and thefirst unit is that the other end of conduit 9 opens into the side ofcavity 8 rather than into a second cavity in the unit. As will be noted,the return unit has only one passageway or pipe. The connection betweenthe units 1 and 7 is shown in section. A conduit 10 passes through thecavities 4 and S in units 1 and 7, respectively. The ends 11 and 12 ofconduit 10 are slip-fitted into the open ends of conduits or passageways2 and 9 respectively. The ends of the conduit and the open ends of therespective passageways are of the same cross-sectional configuration,varying in size just sufiiciently to provide a tight slip-fit and asubstantially fluidtight joint. After the ends 11 and 12 of conduit 10have been seated in the open ends of the passageways 2 and 9, the outersurfaces of the passageways may be deformed in the area of their innercontact surface with the ends 11 and 12 of the conduit 10 to provide amore secure and fiuidtight joint. The deformation may be provided by anyconventional means, such as a hammer blow transmitted to the conduitthrough a suitable blunt shaped punch or similar tool. A larger secondconduit 13 encases and is spaced from the first conduit and has its ends14 and 15 fitted in the cavities 4i and 8, respectively. The ends ofconduit 13 may be received in the openings 4 and 8 by a fiuidtightslip-fit, with or without deformation of the connection cavity, or theends may be secured in the cavity by welding as shown at 16 or by athreaded connection (not shown) or other positive securing means. Supplyand discharge conduits 31 and 32 are seated in the passageway 2 and theadjacent connection cavity 3, respectively, in the same manner asconduits 10 and 13 described above.

Figure 2 shows a modified form of the joint shown in Figures 1 and 3.Here the end portion 20 of passageway 17 opens out through theperipheral edge 5 of the unit, and the passageway is provided with arestricted portion 18. A second passageway 19, similar to passageway 6of plate 1, opens into the side of the conduit end portion 2!). Conduits21 and 22 engage the restricted passageway portion 18 and the endportion 29, respectively, in the same manner as in the joints previouslydescribed. The conduit 22 may be welded or otherwise positively securedto the cavity mouth as shown at 16.

Figure 4 shows another modification of the joint structure wherein theends 23 and 24 of the two conduits, and the conduit receiving portions25 and 26 of the unit are provided with mating wedging surfaces ratherthan with the straight slip-fitting surfaces shown in Figures 1 and 3.The larger conduit may be welded or otherwise positively secured to thecavity mouth, as at 16.

One other modification of the individual joint should be noted. InFigure 5 the conduit 27 is of the same diameter throughout its lengthbut has a. taper beginning slightly inwardly of the opening ofpassageway into passageway 2'. and increasing in diameter toward theperipheral opening. The smaller conduit 28 is provided with an enlargedportion of any conventional type, such as a flange 29 formed on an endof the conduit, which is forced into the passageway sufiiciently far topass opening 30.

As should be apparent from the above description. the units can bequickly assembled by inserting an end of the smaller conduit through theconnection cavity in one of-the units, until it seats in the passagewayopening and then inserting the larger conduit into the peripheralopening of the connection cavity. Similarly, the other ends of theconduits may be inserted into the second unit. The larger conduit may bewelded or otherwise positively joined to the peripheral edges of theunits. As is most clearly seen in the sectional portion of Figure l, bywelding the ends of the larger conduit 13 to the mouth of the cavities 4and 8, the smaller conduit 1%) is secured in place between the ends ofconduits 2 and 9. The units .1 and 7 are integrally joined in fixedrelationship by the conduit 13, the smaller conduit 10 is protected fromdamage by being encased in the larger conduit, and the fluid circuit iscompleted with a minimum of external openings in the units.

When the inner connecting conduits are of flexible or pliable materialthey provide several advantages. Primarily they wiil bend or twistrather than snap or brea. as they expand or contract because of changesin temperature. Also flexible or pliable conduit facilitates assemblywhen it is necessary to provide bends in the conduits, as shown at 31and 32.

The fluid circuit is as follows. Fluid which may be introduced throughthe small conduit 31, flows through the passageway 2 and out through thesmall conduit 1% into passageway 9 in the second unit 7, into cavity 8,through conduit 13 into cavity 4 of unit 1, then through passageway 6into cavity 3 and out through the conduit 32. As many intermediate heatexchanger units as are desired may be inserted between units 1 and 7,utilizing connections, for example, such as illustrated at 10 and 13,and 31 and 32.

The use of heat exchanger units formed in this manner and connected toeach other as described above, materially reduces the cost offabrication by eliminating the necessity of additional external openingsthrough the units. Furthermore, by fabricating the return passageways,such as 6, integrally with the plates the additional expense of separatepiping is eliminated. Ease of assembly is facilitated by the use of slipor wedge fitted joints on the smaller connecting conduits, as 19. Thenumber of external joints is substantially reduced which reduces thepossibility of external leaks. By having the supply and return conduitjoints related in the manner described the temperature at the joint willremain more nearly the same as the temperature of the remainder of theunit. For example, the joint herein described will tend to prevent theformation of excessive frost if the joint is in a refrigerating system.

It is to be understood that although this invention is intended for useprimarily in conjunction with units as described in the aforementionedpatents, it is not to be limited to this embodiment and is equally welladapted to use in coils formed of conventional tubing. It is also to beunderstood that this invention is not to be limited to any particularmaterial nor is its application limited to use in heat exchangers.Although several specific modifications and details are set forth in theforegoing, it will be understood that various changes may be madewithout departing from the spirit and scope of this invention, and thatthis invention is therefore not to be limited to such specificmodifications and details except as set forth in the appendent claims.

We claim:

1. An assembly comprising a plurality of heat exchanger units, each unithaving a passageway with an open end portion, a pipe having an endentering said open end portion of the passageway in each unit andsubstantially fiuidtight means connecting the pipe end and saidpassageway in each unit, a second pipe encasing said first pipe andhaving an end adjacent each open end portion and substantiallyfiuidtight means connecting said second pipe ends and the respectiveopen end portions of said passageways, and a second passageway openinginto each open end portion.

2. The assembly of claim 1 wherein said second passageway opening isbetween said means.

3. The assembly of claim 1 wherein the inside diameter of said secondpipe is substantially greater than the outside diameter of said firstpipe.

4. The structure of claim 1 wherein said second means comprises a weldedjoint.

5. A heat exchanger assembly comprising at least one basic unit and areturn unit, a basic unit comprising a pair of connecting portions and apair of passageways each opening into and interconnecting saidconnecting portions; said return unit comprising a connecting portionand a passageway having end portions opening into said connectingportion; fluid conveying means interconnecting each unit of said heatexchanger assembly with another unit, said means comprising a firstconduit having ends each received in a connecting portion ofinterconnected units and means providing a substantially fluid tightconnection between each of said conduit ends and one of said passagewaysopening into each of the respective connecting portions, a secondconduit encasing said first conduit and having ends opening into therespective connecting portions which receive said first conduit, a fluidconveying space between said first and second conduits and meansproviding a substantially fluid tight connection between each end ofsaid second conduit and the adjacent connecting portion, whereby a fluidconveying circuit is completed throughout the units with the 2,766,019 56 passageways which open into one of said connecting porconnectionbetween said second service conduit and said tions providing an inletand outlet, respectively, in the connecting portion whereby a continuousfluid circuit is heat exchanger assembly. established between saidservice conduits.

6. The heat exchanger assembly of claim 5 and a service conduit receivedin the last said connecting por- 5 References Cited in the file of thispatent tron, a second service conduit encasing said first serviceconduit and a fluid conveying space between said first UNITED STATESPATENTS and second service conduits, means providing a substan- 70 ,90Murgatroyd Sept. 9, 1902 tially fluidtight connection between said firstservice con F duit and a passageway opening into the last said connectl0FOREI GI\ I PATENTS ing portion and means providing a substantiallyfiuidtight 10,924 Great Brltaln May 12, 1904

